Financial statements for the first half of 2017 show the city spent an additional $25 million on policing, $24 million more on firefighters and $16 million more on blue collar workers.

But the city saved $10 million this year in snow removal operations.

Last year, Montreal had a surplus of $139 million.

The mayoral candidate for Projet Montréal, Valérie Plante, said the deficit is an example of the Coderre administration's financial mismanagement.

"I know my opponent talked about unforeseen issues in the collective agreements and everything related to working relationships, but I think we can see where the money went," Plante said, reiterating her concern about the cost of the 375th anniversary celebrations, which reportedly cost the city $1 billion.

The price of this summer's Formula E event is said to have come in at $25 million — with an additional $5.3 million approved after the race — though organizers say data on the exact cost won't be available until after the mayoral election.

Plante has committed to establishing an "accountability commission" to avoid cost overruns.

It would be responsible for monitoring major city projects in order to "avoid unpleasant surprises in terms of quality of work and costs," Plante said.